Explaining Retention in Community-Based Movement Organizations

An individual\u27s initial acceptance of a recruitment pitch from a community-based social movement organization is usually based upon minimal information about the group and its efforts. It is only during the subsequent period of orientation that new members begin to learn more about the organization. During this period, the retention of new members is dependent on the successful alignment of individual and organizational frames. The failure to achieve such an alignment is likely to result in the new member\u27s departure from the organization. This study explores the frame alignment process during early orientation to community-based SMOs. Using nineteen qualitative interviews with three different community organizing efforts in Baltimore, the study suggests that organizational members feel most motivated to continue involvement when they feel that the organization is effective

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements